Genomic epidemiology of sporadic human Brucella melitensis cases in Malaysia through whole genome analysis / Jama’ayah Mohamed Zahidi @ Ahmad Bakri

Brucella melitensis is the most pathogenic and genetically diverged species within the genus Brucella. In Malaysia, human infections by B. melitensis are reported yearly and the cases are primarily sporadic. Whole genome sequencing (WGS) analysis of B. melitensis strains can provide high-quality information for genotyping, monitoring and trace-back purposes in epidemiological studies. This research aim is to determine the genetic relatedness of local B. melitensis strains compared to strains from other geographical locations and to study the genetic variation of these local B. melitensis strains isolated from sporadic human infections. In this study, whole genomic analysis of 25 sporadic human B. melitensis cases in Malaysia and 75 genome sequences of B. melitensis retrieved from the NCBI database. From a total of 100 genome sequences, thirty-four Malaysian strains (25 sporadic isolates in this study, six human isolates from other studies and three animal isolates) can be grouped into genotype II and segregated into a distinct lineage clade of South-East Asian (SEA). Phylogenetics analysis showed that 24 of these 25 strains clustered within a single clade supported by 95% bootstrap. One of the isolate was clustered closely with the Indian isolates strain Bm IND1.